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Eras & periods

Every run targets one era (also called a period), passed as --period. An era is a CMS data-taking period; choosing one selects the matching datasets, corrections and NanoAOD version.

Run 3 eras (current)

--period Description √s NanoAOD
Run3_2022 2022, pre-ECAL repair 13.6 TeV v12
Run3_2022EE 2022, post-ECAL repair ("EE") 13.6 TeV v12
Run3_2023 2023, pre-BPix 13.6 TeV v13
Run3_2023BPix 2023, post-BPix install 13.6 TeV v13
Run3_2024 2024 13.6 TeV v15
Run3_2025 2025 13.6 TeV v15
Run3_2026 2026 13.6 TeV v15

Run 2 eras (legacy)

Run2_2016_HIPM, Run2_2016, Run2_2017, Run2_2018 (13 TeV). Still defined, but new development targets Run 3.

Why the split into sub-eras?

The detector and its calibration change within a year, so CMS treats those segments as separate eras for analysis:

  • 2022 splits at the ECAL endcap repair → Run3_2022 (before) and Run3_2022EE (after).
  • 2023 splits at the pixel-detector "BPix" installation → Run3_2023 and Run3_2023BPix.

Each sub-era has its own corrections and luminosity, which is exactly why the configuration system has a per-era layer: FLAF/config/<era>/ and <analysis>/config/<era>/ carry the era-specific datasets and overrides.

What an era controls

  • Datasets — config/<era>/datasets.yaml lists the samples available for that era, including the correct NanoAOD version path on DAS.
  • NanoAOD version — the table above; the dataset entries point at the right vNN campaign.
  • Corrections — pileup, b-tagging, trigger and other scale factors are era-specific.
  • Signals — resonant/non-resonant signals exist for some eras and not others. For Run3_2024, VBF and non-resonant ggF HH are on DAS (new Par- naming); resonant Radion/BulkGraviton and X→YH→2B2W are not.
  • 2024/2025/2026 shared MC — there is no dedicated 2025 or 2026 MC campaign. All three years use the Summer24 NanoAOD, but jet, PU and tau corrections differ, so AnaTuple production runs once per era. Run3_2025 and Run3_2026 set reuse_mc_from_era: Run3_2024 so the 2024 MC dataset list (and the shared_mc split) is reused. Each production stores weight_base (all events, this year's luminosity; use for a single-year run) and weight_base_cmb (the same events split by residue between 2024, 2025 and 2026; use for a combined run). The split applies only to MC; data keeps the full year in weight_base_cmb. Select which branch histograms use with weight_base_branch. shared_mc lives only on the source era (Run3_2024): a 17:17:4 residue target over modulus 38 (Run3_2024: [ 0, 16 ], Run3_2025: [ 17, 33 ], Run3_2026: [ 34, 37 ]), matching the recorded luminosities 109948.18 : 110730.86 : 25843.26. The actual event split need not match that target. AnaTupleFileTask therefore stores two denominators: the full-sample sum (for weight_base) and the in-era sum (for weight_base_cmb). Each weight is gen × lumi × xs × PU / its_denominator, so both yields stay L·σ. HistTuple multiplies the AnaTuple column named by weight_base_branch (weight_base for a single-year run, weight_base_cmb for the combined 24+25+26 run). Until official UParTAK4 shape files exist, 2024+ era overlays omit btag.normCacheProducer, so HistTuple does not depend on the global BtagShape cache. modes.<stage>: none still loads the correction (needed for WP-id branches) but does not apply scale factors. Missing uncs_to_exclude era keys default to an empty list. The 2026 EGM folder has scale/smear files but no electron.json, so Electron-ID-SF is loaded from the 2025 file and evaluated with year 2025Prompt (not 2026Prompt).

Running several eras

A task runs one era at a time. To cover multiple eras, launch the task once per era (often scripted), or, in CI, list them in the *_eras variable (e.g. Run3_2022 Run3_2022EE Run3_2023 Run3_2023BPix Run3_2024 Run3_2025 Run3_2026). See the integration pipeline. For a 2024+2025+2026 combination, run each era with weight_base_branch: weight_base_cmb and add the histograms.

--period must match an existing era directory

If you pass an era that has no config/<era>/ (or whose datasets are not defined), config loading fails — and if a run unexpectedly drops into InputFileTask and queries Rucio for nothing, a wrong --period/--version combination is the usual cause. See Troubleshooting.

Adding a new era

Adding an era means creating its per-era config directories in both the framework and the analysis, wiring it into the CI era lists, and listing it in test-setup-loading. The full procedure is in Datasets.